Friction clutch draft gear with removable rear wall



1968 A. L. ZANOW .FRICTION CLUTCH DRAFT GEAR WITH REMOVABLE REAR WALL Filed Jan. 4, 1967 United States Patent O 3,403,790 FRICTION CLUTCH DRAFT GEAR WITH REMOVABLE REAR WALL Andrey L. Zanow, Cleveland, Ohio, assignor to Midland- Ross Corporation, Cleveland, Ohio, a corporation of Ohio Filed Jan. 4, 1967, Ser. No. 607,323 5 Claims. (Cl. 213-42) ABSTRACT OF THE DISCLOSURE A friction type draft gear for a railway vehicle having a cushion-actuated friction clutch. The casing of the draft gear has a rear open-end opposite its clutch-receiving end, projecting rear end wall portions on opposite sides of the casing body, and a rear plate-like follower adapted to interlock with the end wall portions for longitudinal retention of the follower in the draft gear body. The follower, when moved from a transverse exterior position into the grip ofthe rear casing portions and in proper registry with the casing walls, is then movable forward relative to the rear casing portions to effect transverse interlocking relationship with the casing body. Adjustable or detachable elements hold the follower forward to entrap the follower within the casing body.

The draft gear described hereinbelow was evolved through efforts to provide an improved rubber cushion friction-clutch draft gear even though the improvements taught herein are applicable, for example, to a frictionclutch type of draft gear utilizing steel coil springs. The invention is better understood if it is realized that a friction-clutch draft gear generates during operation two basic forces. The smaller of these two is that arising Within the cushion as a result of compression of the draft gear. The other preponderantly greater force is that generated within the friction clutch through application of the smaller cushion force to a rear portion of the clutch as a forward portion of the clutch is subjected to a third overwhelming force sufficient to cause compression of the draft gear.

Rubber cushion draft gears of well-known design and commercial importance have a casing of which the cushion compartment is of rectangular cross section. This compartment is wider in the horizontal transverse direction than the vertical and has top and bottom walls with the sides open. In assembling the prior art gear, the multiple-pad rubber cushion is inserted in a state of precompression through an open side of the casing. The top and bottom walls join integrally with the rear vertical Wall of the compartment. In this type of gear, all forces received by the gear from an external source are concentrated in the two walls of the cushion compartment and the rear wall which engages the two stops normally attached to opposite sides of the center sill. As a result, the top, bottom, and rear wall of the cushion compartment are of substantial thickness to withstand the occasional extremely high forces encountered under conditions such as extremely cold weather which substantially stiffens the cushion. In spite of the thickness of these walls, a criticism of this type of gear is that the casing 3,403,790 Patented Oct. 1, 1968 to shift laterally when the cushion is relaxed. The tendency in lateral shifting increases as the rubber pads assume a permanent set of reduced thickness during their normal service life.

Hence, an important object of the invention is to provide a friction-type draft gear for use in standard draft gear pockets of present day railway vehicles in which there is a high degree of utilization of the space potentially available for the cushion of the draft gear without the sacrifice of overall casing wall strength.

It is especially an object to provide a rubber cushion for a friction-clutch draft gear of improved design which is easily assembled, to provide good lateral support of the cushioning medium used to activate the clutch, and to provide distribution of the primary forces imposed on the gear in a manner to allow reduction of the wall thicknesses, increased space for a cushioning unit, and easy assembly of the draft gear.

As there are some in the trade who object to the appearance of the open-side type of draft gear, it is an object to provide a gear having a casing with an uncluttered outward appearance substantially enclosed from the atmosphere to avoid the collection of dirt, rain, ice, etc.

The above and other objects are achieved in a draft gear which has a casing forming a barrel-like front portion for housing a friction-clutch mechanism and a rear cushion-receiving compartment circumscribed by four walls which face a longitudinal axis of the gear along a pair of perpendicular transverse axes. The four Walls are arranged in two pairs of which one pair is longer than the other by rear portions thereof which extend beyond the end surfaces of the shorter pair of walls.

The draft gear further includes a follower which may be transferred to a position laterally outside the casing body to a position between the end portions of the longer pair of walls. The follower and the end portions have guide means, such as parallel flanges, which overlap in a direction transverse to the axis and the length of the flanges causing the follower to move along a path parallel to the wall portions when moved inwardly or outwardly of the cushion compartment. The follower has a front section which fits within the inner periphery of the four compartment walls when the follower is moved slightly forwardly with respect to its transverse path into the casing end.

The draft gear also includes means, such as a key inserted between each side wall flange and the adjacent follower flange to secure the follower in a position of entrapment within the end of the compartment wall wherein its front section is circumscribed by the compartment walls.

In the drawing with respect to which the invention is described:

FIG. 1 is an exploded perspective view of components of a draft gear in accordance with this invention;

FIG. 2 is a fragmentary plan view with elements of a center sill and draft gear shown in section, illustrating a rear portion of the draft gear of FIG. 1 in an assembled condition as positioned against a rear center sill stop;

FIG. 3 is a fragmentary view in section taken along line III-III of FIG. 2;

FIG. 4 is a fragmentary schematic elevation with parts :broken away illustrating a draft gear in accordance with FIGS. 1 and 2, and equipment for installing the rear wall or follower thereof at an intermediate stage of installation;

FIG. 5 is a fragmentary elevation of parts broken away and of the draft gear installation equipment of FIG. 4 at a stage of assembly after completion of the step of FIG. 4 wherein the equipment is further used to install a key for locking the rear follower of the easing into entrapped condition; and

FIG. 6 is a plan view predominantly in section along a medial horizontal plane of the draft gear of the previous figures.

FIG. 1 portrays, in disassembled state, various components of a draft gear 5 which are pertinent to the present invention. The components of a friction clutch mechanism housed in the front barrel 6 of the casing 7, shown in FIG. 5, may be entirely conventional. Hence, details thereof are not essential to a description of this invention.

The present invention is in essence related to a four wall cushion compartment, such as compartment 8 and a configuration of the open rear end of this compartment, and a rear wall or follower 9 which confines a resilient cushioning units 11 internally of the compartment 8. The unit 11 is constructed in a well-known manner from a series of metal plates 14 and pads of rubber 15 bonded to adjacent plates. The cushion may comprise a series of pads comprising a plate 14 and a layer of rubber bonded to each side of the plate. The unit 11 is shaped so that the plates 14 conform loosely to an interior transverse cross section of the compartment 8. Measured along the longitudinal axis of MM of the draft gear, the unit 11 has a length slightly exceeding the interior region of the compartment 8 causing it to be placed in a state of initial compression when confined between a front spring seat 17 and the rear follower 9 in the neutral condition of the draft gear as illustrated in FIG. 5.

For accommodating the rear follower 9, the spring compartment 8 of the casing 7 is preferably of four-wall construction as shown wherein each wall faces along a pair of perpendicular axes in transverse relation to the longitudinal axis MM with the result that side walls 18, 19 are opposite, parallel and longer than top and bottom walls 21, 22 which are also parallel. The walls 18, 19 are rendered longer than walls 21, 22 by end portions 23, 24 which extend in the longitudinal direction of the gear beyond the end surfaces 25, 26 of the top and bottom walls 21, 22, The side walls 18, 19 have rectilinear recesses 28, 29 which extend in a transverse plane at right angles with the axis M-M the full width or height of the side walls 18, 19. The grooves 28, 29 have a width in the longitudinal direction of the draft gear partly within the side-wall end portions 23, 24 defined above and extend forwardly beyond a transverse plane N-N shown in FIG. 2 to be disposed forwardly of the transverse plane which contains the end surfaces 25, 26 of top and bottom walls.

The recesses 28, 29 delineate flanges 33, 34 on end portions 23, 24, respectively, which extend inwardly toward the axis MM but not beyond the planes of the inner surfaces of the walls 18, 19. This configuration results in maximum utilization of the center sill draft gear pocket space and maximum space within the spring compartment S for a cushion. Stated in another way, the depth of grooves 28, 29 is preferably formed within the thickness of the walls 18, 19.

The rear follower 9 has flanges 37, 38 which protrude in the normally transverse horizontal direction of the draft gear in opposite directions from the draft gear axis MM. Flanges 37, 38 are located relative to the longitudinal dimension of the follower 9 to enter and be received in the grooves 28, 29 when the follower is passed transversely over the end surface or 26 of the wall 21 or 22, respectively.

The rear section of the follower 9 has a dimension d (see FIG. 1) which does not include the flanges 37, 38 and enables the rear section of the follower to be received between the casing flanges 33, 34. The rear section extends in a vertical direction beyond the flanges 37, 38 as top and bottom flanges 41, 42 to overlap end surfaces 25, 26 of the top and bottom casing.

The front surfaces (see surface 43 of flange 41) of the flanges 41, 42 are located rearwardly of the frontmost surface 44 of the follower walls, although the flanges 41,

42 overlap to some extent with the side flanges 37, 38 in the longitudinal direction of the draft gear. Flanges 37; 38 face frontwardly within the surface 44.

The flanges 41, 42 thus provide front-facing shoulders which are engageable with the end surfaces 25, 26 and limit the forward movement of the follower 9 into the spring compartment as defined by the four casing walls.

Referring now to FIGS. 4 and 5, a-mode of assembling the draft gear is partially illustrated. For. example, a draft gear may be clamped between a base member 45 and another clamping member 46 tightened thereagain'st by a pair of screws, such as turn-screw 47, with components of the friction clutch and the cushion 11 placed therein. Preliminary to the stage of assembly shown in FIG. 3, a block or dummy follower 48 of simple block design having a length adapting it to rest on the surfaces 25 and 26 and a width adapting it to fit between the flanges 33, 34, and a thickness slightly greater than'that of the follower 9, is placed over the uncompressed cushion 11 in a longitudinal alignment with the casing such that it will engage the surfaces 25, 26. A press platen 49 is brought into engagement with the platen 48 while in axially-centered relation with'the casings and adjusted toward the casing until the dummy follower 48 nearly contacts the surfaces 25 and 26. I

Thereafter, the follower 9 is placed in a njalignrnent wherein its length is perpendicular to gear axis MM which may be obtained by resting on the upper surface 51 of the member 45 in flush relationship with the side wall end surface 25. The follower 9 is then thrust in a direction at right angle relation with the axis MM by a platen 52 which in turn forces the dummy follower 48 out from under the platen 49, as shown in FIG. 4. At the completion of this operation, the block 48 is replaced within the end of the draft gear casing by the follower 9. Thereupon, with the block 48 now free of the draft gear and the platen 49, the follower 9 is forced inwardly of the draft gear casing, as shown in FIG. 5, to a position wherein the flanges 41, 42 rest on the end wall surfaces 25, 26. In this position of the follower 9, gaps are created between the follower flanges 37, 38 and the wall flanges 33, 34, re spectively, which are adequate for loosely receiving a pair of keys 54, 55 in the manner as shown with respect to key 54 in FIG. 4. When the keys are fully inserted, the curved upturned end portions thereof may bewelded to the ends of the flanges 33, 34 as shown in FIGS. 2 and ,3. The keys 54, 55 are of a thickness sufficient to dispose the followers front section, including the flanges 37, 38 partially forward in direction of the end wall surfaces 25, 26. Thus, the thickness of the keys 54, 55 in the lengthwise direction of the gear is greater than the magnitude of overlap of the front section of the follower 9 with the rear portions of top and bottom walls 21, 22. The follower 9 is thus locked into the casing with the four walls thereof in circumscribing relation with the front section of the follower 9. This relationship is maintained independently of the cushion 11 even though the latter is in a state of initial compression thereagainst.

The notches at the ends of the end wall surfaces. 25, 26, e.g., notches 58, 59 of the wall 21, are provided in the original castings of the casing to place a fillet at the junction of the top or bottom wall with a side wall (see fillet 58) sufflciently forward in the casing to avoid interference with insertion of the keys 54, 55 and to facilitate access by a machine tool to the surfaces 25, 26 sincethese surfaces need to be rather closely correlated withthe flanges 33, 34 for admitting the follower 9.

At neutral position, the draft gear 5 is received in the draft gear pocket of a center sill 61 with its front follower 62 engaging front stops (not shown) attached to the sill and the rear follower 9 engaging the rear stops (see rear stop 69). As may be understood from FIG. 2, buff action, i.e., a rearwardly directed force on the front follower, will cause the rear follower 9 to recede frontwardlyinto the casing 8 against cushion pressure, and allow the rear end surfaces of the casing walls 18, 19 to engage the rear stops. To enable such operation, the gap between such end surfaces of walls 18, 19 and the rear stops must be less than the gap between the shoulder surfaces 43 of the follower 9 and the end surfaces 25, 26 of walls 21, 22.

The arrangement of gaps just described has the purpose of avoiding subjection of the follower 9 to full buff forces imposed on the draft gear; they are, instead, sustained by the integrated four-wall casing structure through the rear ends of walls 18 and 19. However, in draft action, a yoke normally encircles the draft gear along a central vertical longitudinal plane. The yoke (not shown) engages the back side of the follower 9 and forces the follower against end surfaces 25, 26 of walls 18, 19 without imposing any substantial beam loads on the follower 9. The arrangement of gaps described above has the further important purposes of 1) protecting the relatively weak flanges 33, 34 from imposition of full buffing action, and (2) providing suflicient room for manufacturing parts under conventional casting tolerances.

The invention has been described by way of example with respect to a cushioning means comprising conventional rubber pads. As indicated previously herein, other type of cushioning means are within the scope of the invention, such as volute or helical springs of the various types known to the draft gear art, or a cushioning arrangement consisting primarily or partly of a hydraulic snubber. For simplifying description, the invention has been described with respect to a draft gear type in which it is currently and urgently incorporated, i.e., one wherein the cushioning means actuates a friction-clutch. However, the invention in being primarily concerned with an easily-removable end wall construction of the cushion-receiving compartment, is applicable generally to all draft gears providing suoh a compartment.

What is claimed is:

1. Railway car draft gear comprising:

a casing having a rear cushion-receiving compartment having a rear open end, said rear compartment terminating rearwardly in four walls facing a longitudinal axis of the gear along a pair of perpendicular transverse axes, and

a follower receivable in said open end and having a front section receivable within the rearmost region of the compartment circumscribed by said walls;

one pair of said walls being transversely rectilinear and defining rear end portions disposed rearwardly of rear end surfaces of the other pair of shorter walls;

transverse guide means on the follower and said wall end portions enabling said follower to be moved along a path parallel to said wall portions from a position transversely outside the compartment to a position between said wall portions and longitudinally outward relative to said rear end surfaces, said guide means limiting movement of said follower to said path with respect to an outward longitudinal direction of the gear but enabling movement of the follower toward the front of the gear when in registry with said open end; and

support means supported by the compartment against the follower for holding the follower inward from said path to dispose it in a condition of entrapment within the compartment with its front section in said region.

2. The draft gear of claim 1 wherein:

said guide means comprises flanges on the follower and said rear casing portions which overlap in a direction transversely of said axis.

3. The draft gear of claim 1 wherein:

said guide means comprises each of said wall portions and its parent wall defining a groove along its inner surface, and said follower has flanges along one pair of its opposite sides received in said grooves when the follower is in said registry; and

said support means comprises a key insertable into a clearance between each flange and the rear side of each groove, said keys and said grooves being of sufficient width in the longitudinal direction of the draft gear to dispose said front follower section forwardly of said end surfaces of said other two walls in a position of entrapment within casing.

4. The draft gear of claim 1 wherein:

said guide means comprises each of said wall portions and each parent wall thereof has a groove along its inner surface, and said front section of the follower includes flanges along one pair of opposite sides thereof received in said grooves when the follower is in said registry, said grooves defining end flanges as rear extremities of said end wall portions;

said follower has a rear section of less width than said front section including said follower flanges adapted to fit in close but loose juxtaposition with said end flanges;

said groove has suflicient width lengthwise of the gear to enable forward movement of the follower to a forward position disposing said front section at least partly forward of said wall end surface; and

said support means comprises a pair of keys received in the clearances occurring between said follower flanges and said end flanges at said forward position of the follower.

5. The draft gear of claim 1 wherein:

said guide means comprises flanges at the rear extremities of said longer walls, the front sides of said flanges defining the rear sides of coextensive grooves in said walls having front sides disposed frontward of said wall end surfaces, and flanges on said front follower section in forward transversely overlapping engageable relation with said wall flanges;

said support means is a pair of keys insertable between said wall flanges and said follower flanges, the width of said keys in the longitudinal direction of the gear being greater than the magnitude of overlapping of said front section with said shorter walls affected by said keys when in operable position.

References Cited UNITED STATES PATENTS 2,076,769 4/1937 Dentler 2l324 2,326,288 8/1943 Dath 2l322 2,903,143 9/1959 Gadbois 2l322 2,953,260 9/1960 Danielson 213-32 DRAYTON E. HOFFMAN, Primary Examiner. 

